shellcheck: add ignore for files currently failing

An upcoming change in openbmc-build-scripts will enable shellcheck
everywhere.  Add currently failing files to the .shellcheck-ignore.
The expectation is that the maintainers will resolve the shellcheck
issues as time is available.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I88fb6c71801141c08255e8f8deb6cf495b3624d9
1 file changed